EIGENMANN: the freshwater fishes of BRITISH GUIANA 125 



7. Platystacus cotylephorus Bloch. 

 Platystacus cotylephorus Block, Ausl. Fische, VIII, 1794, 54, pi. 372. — Bloch and 



Schneider, Syst. Ichth., 1801, 372. — Bleeker, " Silures de Suriname," 1864, 



95 (Surinam). — Eigenmann and Eigenmann, Proc. Cal. Acad. Sci., (2), II, 



1889, 50 (Vigia; Para; Tajapuru); Occasional Papers Cal. Acad. Sci., I, 1890, 



21 (Vigia; Para; Tajapuru). — Eigenmann, Repts. Princeton Univ. Exp. 



Patagonia, III, 1910, 300. 

 Silurus cotylephorus Lacepede, Hist. Nat. Poiss., V, 1803, 78. 

 Aspredo cotylephorus Gunther, Catalogue, V, 1864, 269 (Surinam). 

 Silurus hexadayctlus Lacepede, Hist. Nat. Poiss., V, 1803, 82. 

 Aspredo sex-cirrhis Cuvier and Valenciennes, Hist. Nat. Poiss., XV, 1840,441. 

 Aspredo spectrum Gronow, Cat. Fish, ed. Gray, 1854, 137. 



I did not observe this species myself, but several specimens were taken by 

 Mr. Ellis. 



A. 53-57; greatest width, before pectoral spine, 5.5-6.5 in the length; length 

 of head to gill-opening 9 in the length, with the caudal fin. 



Head greatly depressed, narrowed forward; interorbital width 3.5 in the dis- 

 tance from base of pectoral to tip of snout ; width of mouth equals the interorbital 

 plus the orbits, the snout projecting half its length. Premaxillaries with two rhom- 

 boidal patches of villiform teeth, lower jaw with wider patches of similar teeth. 

 Maxillary barbels reaching to gill-opening, mental not to post-mental barbels, which 

 are as long as or a little longer than the width of the mouth. Coracoid processes 

 slightly diverging backward, the length of the processes 1.25 in the distance be- 

 tween their bases. Humeral processes co-extensive with but not overlapping the 

 coracoid processes. Pectoral pore below the tip of humeral process. 



Distance of dorsal fin from tip of snout 3.5-3.75 in the length; first dorsal ray 

 scarcely prolonged. Outermost caudal rays prolonged. Four rows of papillae on 

 the sides. Dark brown, blotched with fighter. 



Subfamily Bunocephalin^. 



Bunocephalus Kner. 



Bunocephalus Kner, SB. Akad. Wiss. Wien, XVII, 1855, 95. — Bleeker, Nederl. 



Tijdschr. Dierk., I, 1863, 118 (verrucosus). 



Type, Platystacus verrucosus Bloch. 



Tail short; dorsal well-developed; barbels 6; head depressed, without i)rom- 



inent knobs. 



Key to the Species op Bunocephalus. 



a. A. 6; distance from snout to dorsal 2.75-3 in the lengtli with the caudal ; width 3.5 in the 

 length gronovii. 



